1. Field of the Invention
The present invention relates generally to centrifugal separation equipment employing an air cooling system to maintain the temperature of specimens being separated at approximately room temperature during centrifugation, and, more particularly, to such equipment adapted for use with hazardous materials.
2. Description of the Prior Art
Centrifuges are primarily used to separate relatively solid particles, such as blood cells, from fluids, and are generally employed in a laboratory environment. Typically, centrifuge equipment includes a rotor assembly positioned within a rotor chamber in a centrifuge housing. The housing usually includes a latchable lid or cover to allow access to the rotor for placement or removal of samples, and to enclose the rotor when centrifugation of specimens is occurring.
Because the rotor spins at high speeds within the rotor chamber, heat builds up due to induced air turbulence therein. This heat build-up is not desirable because it can effect the samples being separated, and can alter the results of diagnostic procedures involving the samples.
One solution to this problem has been to provide refrigerated centrifugal separation equipment, wherein evaporator coils of a refrigeration system are wrapped around the rotor chamber walls to remove heat from within the chamber. Typically, such refrigerated centrifuge equipment is more costly, and is prone to problems resulting from frost and condensation formation within the refrigerated rotor chamber.
Another approach is to maintain the interior of the rotor chamber at ambient room temperature by providing a stream of cooling air through the rotor chamber to remove heat therefrom. Typically, this is accomplished by providing holes in the cover of the rotor chamber and in some way using the spinning motion of the rotor to propel air into, through, and out of the rotor chamber. This method is a less expensive alternative to refrigeration, and is acceptable for many applications.
However, there are occasions when it is desirable to separate a sample of hazardous material, for example, infected blood, or other materials containing pathogens or other harmful agents. These materials, if introduced into the atmosphere of a laboratory containing the centrifuge, for example, would be potentially harmful to lab personnel or laboratory animals. It has been recognized that conventional air-cooled centrifuge designs may allow harmful materials to be introduced into the cooling air blowing through the rotor chamber, for example, from a defectively sealed sample container, or as a result of a sample container breaking during centrifugation. Since such a leak occurs from a rapidly spinning rotor assembly, the harmful material will likely be introduced into a cooling airstream as an aerosol, which allows the harmful material to travel a considerable distance, and to be drawn into the respiratory tracts of people and animals in the laboratory and beyond.
As a consequence, it has been recognized that containment of hazardous materials is a desirable attribute of air-cooled centrifuge equipment. One approach has been to provide a rotor assembly which contains separately sealed covered sample carriers for containing specimen containers. Such covered carriers provide a barrier to the escape of contaminants over and above the specimen containers placed therein. However, such carriers provide additional work for lab personnel, as conventional devices involve screwing down locking screws to hold lids on such carriers, or twisting threaded lids on and off such carriers.
Moreover, even with such additional containment provisions, it has been noted that it is still possible for hazardous materials to be introduced into a cooling airstream, thereby contaminating the laboratory, if a carrier is improperly sealed by an operator, or is otherwise defective. Because of the relatively high volume of air which must be pushed through the rotor chamber to keep it at ambient temperature, even a small leak can introduce a contaminant or pathogen or other harmful agent over a large area, and some such dispersed hazardous materials may be detrimental even at very small airborne concentrations.
In light of the foregoing, it has been recognized that hazardous aerosol contaminants carried in centrifuge cooling air exhaust is a particularly troubling problem. Centrifugal separation equipment employing air cooling preferably will mitigate the above-described problems. The desirable attributes of a centrifuge of this type should include convenience of function for lab personnel who will be operating the equipment, as well as providing for the safety of people and laboratory animals who may be exposed to air which has been used to cool the centrifuge. The present invention addresses these concerns.